Pressure casting apparatus.



A. W. MORRIS. PRESSURE CASTING APPARATUS.

APPLICATION FILED JULY 18, 19114 1 039 173 Patented Sept. 24, 1912.

' NTOR:

ATTORNEYS ALBERT WOOD MORRIS,

OIQ PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO WETHEE- ILL FINISHEDCASTINGS COMPANY, 01* PHILADELIHIA, PENNSYLVANIA, 4.. COB! POBATION OFPENNSYLVANIA.

PRESSURE CASTING APPARATUS.

Specification of Letters Patent. Application filed July 18, 1911.

Patented Sept. 24, 1912. Serial No. 639,104.

To all whom it may concern:

Be it known that I, ALBERT W. a citizen of the Philadelphia, ofPennsylvania, have invented certain new Mourns, United States, residingat and useful Improvements in Pressure Cast-i lug Apparatus; and I dohereby declare the following to be a full, clear, and exact de scriptionof the invention, such as will enable others skilled in the art to whichit appertains to make and use the same.

This improvement in the art of pressure casting consists primarily inproviding a cylinder in open communication with the air or other elasticfluids in the u'ielting chamber above the molten metal, and a piston. inthat cylinder which is capable of pro ducin" b its inward movement, aJro rcs (.0 b

' of pressure upon the large volume of air sive increase of density ofthe air and a corresponding progressive increase of pressure, from lowto high, upon the molten metal, thereby causing the molten metal toenter quietly, but promptly, through the uptake provided for thepurpose. into the mold,

filling it completely and subjecting it therein to the pressurenecessary during cooling, setting and shrinkage to insure flawless andhomogeneous castings.

In admitting air under pressure to the melting chamber through pipes andvalves, the manipulation of the pressure apparatus as heretoforerequired considrable skill, for the reason that too sudden anapplicapressure tends to cause the metal to spurt into the mold in adivided state and to quickly cool-"therein, leaving imperfections in thefinished casting where the mold was not completely fill'ed, and in someinstances causing subsequent warping in the finished casting because ofthenon-homogcncous condition of its metal. It is possible thatthodifiiculty in securing a gradual application chamber through theadmission of any con siderable quantity of compressed'air thereto isincreased by the sudden expansion of the as it comes in contact Wit themolten metal. This disadvantage is absent when. the air or other elasticfluid to which the pressure is applied is already in contact with theheated metal, as is the case when the before mentioned cylinder andpiston or their equivalents are employed,

county of Philadelphia, State metal in the melting The invention furthercontemplates the en'iployment of valve-controlled hydraulic means foractuating the piston, with the advantage that this mode of control con;-tributes to the uniformity in the successive cycles of operationessential to the production of the best results. I In the accompanyingdrawing, I have illustrated by a vertical sectional view, a pressurecasting furnace embodying the invcution.

Referring to the drawing, A represents the melting chamber preferably ofmetal having a refractory lining a, and supported upon a suitablefoundation B. The melting chamber A is divided by'a partition 0 into amain compartment or reservoir D and a smaller compartment E constitutingan uptake for the metal into the mold. The two compartments D and Ecommunicatebelow the partition, so that molten metal may pass under saidpartition from one to the other. A top plate F closes the meltingchamber A and has prcssure-tight joints with the outer Walls of thechamber and the top edge of the partition 0. 4

A mold G is'mounted above the uptake E, and a port II in the top plate Fpermits the passage of the metal from E into the mold. An open-endedcylinder I is mounted on the top plate F above communicates therewithturc J in the top plate, this aperture J, how" ever, being of such sizethat the bore of the cylinder I and the reservoir I) practically formone chamber.

A piston K working in the when in its upper position as covers a port Yin the walls of said cylinder communicating with the outer atmosphere,so that atmospheric pressure may be established within the meltingchamber before the mold is opened to remove a finished casting.

The cylinder through an apercylinder I, shown, un-

The

the reservoir D and leads, and these pipes Q and S, lead from two of thepassages of the casing of a fourway valve T, the other two passagesthereof being connected to a water-pressure supply pipe U and an exhaustV. he valve T has two ports W and X which allow the water above thepiston O to exhaust through pipe Q, port X and exhaust V, while waterunder pressure passes from supply pipe U through ort' W and pipe S tothe underside oii piston O. This raises the piston 0, piston rod L andpiston K to the position shown in the drawing, when the contents ofreservoir D will be at atmospheric pressure as before stated and themold may be safely opened.

The operation of filling the mold and the formation of a completedcasting is as fol-' lows: The valve T is turned to allow the exhaust ofthe water under piston 0 through pipe S, port W and exhaust V, and thesimultaneous admission of water under pressure from the supply pipe. Uthrough port X and pipe Q, to the upper side of piston O, which willforce piston 0, its piston rod L and the piston K downwardly. Thehydraulic control being positive in its action permits a particularlydelicate control in this organization either by hand. or automaticmeans, as the expansion and compression of the air acted upon do notreact prejudicially upon the source of power. Immediately after thepiston K starts down,

- filled with metal.

bil

under the action of the water pressure above piston 0, it closes theport Y to, the reservoir D and its continued downward movement builds upa constantly increasing pressure in the reservoir D, actingprogressively,

though promptly, upon the surface of the.

molten metal therein to lower its level and to quietly raise the metalin up-take E into the mold G until the mold is entirely The piston Kcontinues to descend after the mold is filled, increasing the pressureupon the cooling metal in the mold as contraction of the metal takesplace, and finally applying the highest pressure as the metalsolidifies. The valve T is then reversedto raise the piston K to itsupper position, lowering the pressure in the melting chamber again tothat of the atmosphere, when the mold may be opened and the castingremoved. The molten metal does not at any time come'into contact withthe piston or cylinder nor with any working part other than the molditself, and the air compressed is that already in contact with theheated metal so that sudden and increasing its pressure, and, on thelip-stroke the air regains its original volume, and in fact, of somewhatgreater volume because of the lowering of the normal level of metal inthe reservoir due to the filling of the mold. To provide for supplyingto the body of entrapped air a further amount suilicient to compensatefor the enlarged capacity due to the lowering of level referred to, theport Y sutlices each time that it is uncovered at the termination of thelip-stroke of the piston.

Having thus described my invention what I claim is:

1 In pressure casting apparatus, the combination with a mold, of amolten metal reservoir for supplying metal to the mold, a cylindercontaining a trapped body of air heated by contact with the uppersurface of the molten metal in the reservoir, a piston for progressivelydiminishing the volume and increasing the density of-said heated trappedbody of air, so as to raise the metal quietly into the mold, and meansfor restoring the trapped body of air to its original volume and forsupplementing its volume by the admission of additional air to saidtrapped body, after a mold is filled, to compensate for the lowering ofthe normal level of the'metal in the reservoir and the increase in sizeof the air chamber incident to such filling; substantially as described.

2. In pressure casting apparatus, the combination with a mold, ot anup-t-ake com-- municating therewith, a molten-metal reservoir forsupplying metal to the lip-take and mold, an open-ended cylinder whosebore is in direct and unrestricted communication with the reservoir, anda piston operating in the cylinder to progressively diminishthe volumeof the body of air trapped be tween the piston and the upper surface ofthe molten metal; substantially as described.

the molten metal, and means for actuating said piston hydraulically;substantially as described.

at. In pressure casting apparatus, the combination with a mold, of anup-take communicating therewith, a molten-metal reservoir for supplyingmetal to the up-take-and mold, an open-ended cylinder whose bore is indirect and unrestricted communication with the reservoir, a pistonoperating in said cylinder to alternately diminish and increase thevolume of the body of air liquid suppl under pressure to said secondtrapped between the piston andthe upper cylinder; su stantmlly asdescribed. 10

. surface of the molten metal, and means for In testimony whereof Iafiix my signaact-uating said piston hydraulically, said ture, inpresence of two'witnesses. means consisting of a second cylinder, :1ALBERT WOOD MORRIS.

' piston in said second cylinder connected to Witnesses:

said first-named piston, and controlling F. J. KING, mechanism for theadmlsslon of a suitable C. NV. TOTHERGILL'.

